1. Field of the Invention
The invention is concerned with gas pressure driven pumps useful for transferring liquid from a vessel to another desired location. For example, such pumps are useful in pumping liquid from deep wells. Further, such pumps are useful in pumping liquid along liquid flow lines such as petroleum pipe lines. Still further they are useful as swimming pool pumps wherein the electrical shock hazard can be reduced by placing the electrical portion thereof (the compressor) far from any water. Yet further, they are useful as beverage, e.g., wine, pumps wherein lubrication problems (where the lubricant in normal pumps can contaminate the wine) are eliminated.
2. Prior Art
The prior art teaches a number of pressure differential operated pumping systems. For example, Mingus et al. in U.S. Pat. No. 1,748,361 teach one such system for pumping water or other liquid from a well and assuring that a constant head of water is available. Smith in U.S. Pat. No. 3,082,698 teaches a water head controlled pump which is operated on a pressure differential and which serves to transfer liquid out of a vessel or a tank. Repp in U.S. Pat. No. 3,422,768 teaches an electric switch operated pumping system which operates responsive to the total head of a liquid within a tank.
The present invention provides an improved system which is substantially independent of the density of the liquid therein and which pumps equal volumes of liquid in each stroke thereof and wherein the sensing means used to control said pumping system provides a unique sensitivity along with a protected construction whereby the relatively sensitive elements of the pumping system are all gas pressure operated.